Device for detecting different steering angles

ABSTRACT

The invention concerns a device having an originator and a receiver unit (10, 11) and a signal-processing device (17) for detecting different steering angles. The device delivers switch signals, for instance, for actuating differential locks. For identifying discrete steering angles the originator unit (10) operates in conjunction with two sensors (12, 13). The proposed steering-angle sensory analysis is preferably used in axles of tractors and construction machines.

The invention concerns a device having an originator unit, a receiverunit, and a signal-processing unit for detecting different steeringangles of a driven wheel of an axle for a motor vehicle.

EP-B1-02 27 660 has disclosed such a device provided for actuating adifferential lock such as used, for instance, in farm tractors orconstruction vehicles. Since the driving devices of such vehicles arebecoming increasingly complex, it is desirable to detect, starting froma straight-ahead drive position, limiting angles of different magnitudesfor each steering direction of a wheel. This is one objective of theinstant invention. In addition, the device must be simply built fromstructural and constructional points of view, and be capable of meetingthe partly unfavorable conditions existing in practice.

The problem on which the invention is based is solved by the fact thatthe originator unit and two sensors, as a receiver unit, work inconjunction for identifying discrete steering angles of the wheel, andthat based on the possible switch conditions of the sensors, switchsignals are made available by means of which the signal-processing unitdetects the steering angles in accordance with a magnitude and directionthereof. The proposed solution has the particular advantage that foreach steering direction of the wheel, specific steering angles can beexactly detected by simple means so that depending on the necessitiescreated by practice, for example, more than one differential lock can beactuated in the input traction of the vehicle depending on the steeringangle. For instance, an arrangement is conceivable where, in thepresence of a first (small) limiting steering angle, a transversedifferential of a front axle is engaged or disengaged, while uponreaching another (larger) limiting steering angle, the differential lockof a longitudinal differential can be engaged. The expert will apply theproposed fundamental solution to similar problems.

An advantageous design of the originator unit is distinguished by havingsectors with leading edges. The leading edges produce switch conditionsof the sensors with which at least two discrete steering angles can bedetected for each steering direction of the wheel.

During the production of the originator unit, it is possible, at a smallexpense, for the sensors to have three steering angles for each steeringdirection of the wheel. In this case, the originator unit has fourleading edges.

A simple solution is obtained when the originator unit is formed by anaxle kingpin.

The arrangement of the sensors can be accomplished in a simple manner bymaking them extend radially to an axis of rotation of the kingpin. Forthis purpose, the sensors are preferably situated adjacently in oneplane and form an angle with each other. They are mounted in bores of anaxle bridge, for instance, by screwing in a thread. Other possiblemanners of fastening are obviously available to the manufacturer.

For the manufacture and also for the operational safety of the device,it is advantageous to pass the connecting wires of the sensors into acommon duct.

Since the sensors must be accessible from outside for servicing andadjustment purposes, it is advantageous to protect them from externalinfluences by a detachable sealing cover.

In order to further protect the sensors against damage, it isadvantageous to place them on the side of the axle bridge remote from aforward direction of travel.

A preferred embodiment of the originator unit distinguishes itself bythe presence of three sectors. The central sector, based on a neutral orstraight-ahead travel position, is formed by a groove. When it isdesired that absolute amounts of the steering angles in the leadingedges or the sectors can be advantageously designed in a manner suchthat the discrete steering angles for each steering direction of thewheel deviate from each other. An especially simple adaptation to thesteering geometry can be obtained with said steps.

Other essential features for the invention, and the advantages resultingtherefrom, are to be understood from the following description of anembodiment.

In the Drawings:

FIG. 1 is a partial, greatly simplified, topview of one axle of a motorvehicle specifically in the area of a steered wheel;

FIG. 2 is a detail in cross section of the arrangement of FIG. 1 alongline II--II of FIG. 1;

FIG. 3 is a topview diagrammatic reproduction of an originator and areceiver unit; and

FIG. 4 is a tabular illustration of discrete steering angles dependingon the possible switching conditions of the receiver unit.

A diagrammatic reproduction, partly cut away, topview of the left,external portion of an axle 1 of a motor vehicle such as a tractor isshown in FIG. 1. The direction of travel is designated with the arrow F.

The axle 1 consists of an axle bridge 2 in which, in particular, an axlehalf shaft not shown is supported. A pivot housing 3, on which alikewise not shown wheel is rotatably supported, is merely indicated andtiltably situated about an axis of rotation D. Part of the pivot housing3 is shown in a terminal position which corresponds to a left turn withthe smallest turning radius.

The area to be seen as partially cut away in FIG. 1 is part of the upperleg 4 of the fork-like end of the axle bridge 2. A blind bore 5 can beseen which serves mainly for supporting an axle kingpin 6. The axlekingpin 6 is a component of the pivot housing 3 and rotates therewitharound the axis of rotation D. For this purpose, the axle kingpin 6, ascan be seen in FIG. 2, is supported on a tapered roller bearing 7 in thetop leg 4 of the axle bridge 2.

On the side of the axle bridge 2, remote from the forward direction oftravel F, are two bores 8 and 9 in the top leg 4. The bores 8 and 9 liein a horizontal plane and are radially oriented with respect to the axisof rotation D.

Different steering angles are detected by the interaction of anoriginator unit 10 with a receiver unit 11 and a signal-processing unit17 which is only diagrammatically indicated.

In the described embodiment of the invention, the originator unit itselfis formed by the axle kingpin 6 (FIG. 2). The receiver unit 11 iscomposed of two sensors 12 and 13 which are inserted in the bores 8 and9. Connecting wires 14 and 15 are housed together in a duct 16 of theaxle bridge 2 and connected with the signal-processing device 17.

Since the sensors 12 and 13 must be accessible for assembly andadjustment purposes, a detachable sealing cover 18 is provided whichprotects the sensors 12 and 13 from external influences. In thediagrammatic drawing according to FIG. 3, a further development of theoriginator unit 10 and the interaction thereof with the receiver unit 11formed by the sensors 12 and 13 can be seen.

The originator unit has all together four leading edges A1, A2, A3 andA4. The leading edges A1 to A4 define three sectors of the originatorunit 10, of which, the central sector is formed by a groove 19 and thetwo adjacent sectors by webs 20 and 21. To make the coordination of theleading edges A1 to A4 with the sensors 12 and 13 intelligible, theswitch points of the sensors 12 and 13 are designated as S1 and S2.

For identifying discrete steering angles, the originator unit 10, withthe leading edges A1 to A4,

For identifying discrete steering angles, the originator unit 10, withthe leading edges A1 to A4, operate in conjunction with the two sensors12 and 13, and the switching points S1 thereof, as the receiver unit 11.The possible switching conditions of the sensors are designated with Ior O. FIG. 4 contains a tabular synopsis of the switching conditions ofthe sensors 12 and 13 depending on specific discrete steering angles α1,α2, α3, α4, α5 and α6 which occur when making a left or right turn.Based on the switching conditions, the signal-processing device canidentify each one of the discrete steering angles α1 to α6 according totheir magnitude and direction. The discrete steering angles α1 to α6,mentioned below or seen from the table of FIG. 4, are to be interpretedas examples.

Discrete steering angles α1, α3 and α5 of 15°, 25° and 30° occur whenmaking a left turn. It must be added for clarification that theoriginator unit 10, when making a left turn, is rotated counterclockwisearound the axis of rotation D. α1 is reached when the leading edge A2 isopposite the switch point S2. At α3, the leading edge A4 is opposite theswitch point S1. A steering angle α5 of 30° is detected when the leadingedge A1 is opposite the switch point S2 of the sensor 13.

When making a right turn, where the originator unit 10 is rotatedclockwise around the axis of rotation D, the following conditionsappear:

The steering angle α2 of 14° is present when the leading edge A1 hasreached the switch point S1. α4, that is a steering angle of 22°, meansthat the leading edge A3 is opposite the switch point S2. A steeringangle α6 of 29°, is reached when the leading edge A2 is opposite theswitch point S1.

The respective switch conditions of the sensors 12 and 13, based on theindicated discrete steering angles α1 to α6, are to be understood fromthe table of FIG. 4. understood that the discrete steering angles α1 toα6 can be respectively varied in a simple manner.

REFERENCE NUMERALS

1 axle

2 axle bridge

3 pivot housing

4 upper leg

5 blind bore

6 axle kingpin

7 tapered roller bearing

8 bore

9 bore

10 originator unit

11 receiver unit

12 sensor

13 sensor

14 connecting wire

15 connecting wire

16 duct

17 signal-processing unit

18 sealing cover

19 groove

20 web

21 web

We claim:
 1. A detection device for detecting discrete steering angle ofa wheel, said device comprising:an originator unit; a receiver unit (11)interacting with said originator unit, said receiver unit comprising twosensors (12, 13); and a signal-processing unit (17), communicating withsaid receiver unit (11), for determining different steering angles of adriven wheel of an axle for a motor vehicle; wherein said originatorunit (10) and said two sensors (12, 13) operate in conjunction with oneanother for identifying a discrete steering angle (α1 to α6) of thewheel and, based upon the possible switch conditions (I, O) of saidsensors (12, 13), said signal-processing unit (17) detects the discretesteering angles (α1 to α6) according to a direction and a magnitude ofthe steering angle and, when the wheel is located in a straight-aheadtravel position and said two sensors are activated, said two sensors(12, 13) are positioned adjacent a web portion of said originator unit(10) and generate an identical switch condition (I or O).
 2. A deviceaccording to the claim 1, wherein said originator unit (10) has aplurality of sectors (19, 20, 21) with leading edges (A1 to A4) whichproduce said switch conditions (I, O) of said sensors (12, 13), and atleast two discrete steering angles (α1 to α6) are detectable for eachdirection of rotation of the wheel from a straight-ahead travelposition.
 3. A device according to claim 2, wherein said originator unit(10) has four leading edges (A1 to A4) in which three discrete steeringangles (α1 to α6) are detectable for each direction of rotation of thewheel from a straight-ahead travel position.
 4. A device according toclaim 1, wherein said originator unit (10) comprises an axle kingpin(6).
 5. A device according to claim 4, wherein said sensors (12, 13)extend radially with respect to an axis of rotation (D) of said axlekingpin (6).
 6. A device according to claim 4, wherein said sensors areassembled, in one plane, adjacent one another in bores (8, 9) of an axlebridge (2) and said sensors form an angle with respect to one another.7. A device according to claim 2, wherein said originator unit (10)includes three serially arranged sectors (19, 20, 21) and the centralsector is formed by a groove (19).
 8. A device according to claim 7,wherein at least one of said leading edges (A1 to A4) and said threesectors (19, 20, 21) is designed in a manner such that the discretesteering angles (α1 to α6) deviate from one another for each steeringdirection of the wheel.
 9. A device according to the claim 1, whereinsaid two sensors, when activated, generate identical switch conditions(I or O), as the switch condition (I or O) generated when the wheel islocated in a straight-ahead travel position, only for a single desiredcontiguous steering angle range during a right-hand turn and for asingle desired contiguous steering angle range during a left-hand turn.10. A detection device for detecting discrete steering angle of a wheel,said device comprising:an originator unit; a receiver unit (11)interacting with said originator unit, said receiver unit comprising twosensors (12, 13); and a signal-processing unit (17), communicating withsaid receiver unit (11), for determining different steering angles of adriven wheel of an axle for a motor vehicle; wherein said originatorunit (10) and said two sensors (12, 13) operate in conjunction with oneanother for identifying a discrete steering angle (α1 to α6) of thewheel and, based upon the possible switch conditions (I, O) of saidsensors (12, 13), said signal-processing unit (17) detects the discretesteering angles (α1 to α6) according to a direction and a magnitude ofthe steering angle, said sensors are assembled in bores (8, 9) of anaxle bridge (2), and connecting wires (14, 15), interconnected with saidsensors (12, 13), are located within a common duct (16) of said axlebridge (2).
 11. A detection device for detecting discrete steering angleof a wheel, said device comprising:an originator unit; a receiver unit(11) interacting with said originator unit, said receiver unitcomprising two sensors (12, 13); and a signal-processing unit (17),communicating with said receiver unit (11), for determining differentsteering angles of a driven wheel of an axle for a motor vehicle;wherein said originator unit (10) and said two sensors (12, 13) operatein conjunction with one another for identifying a discrete steeringangle (α1 to α6) of the wheel and, based upon the possible switchconditions (I, O) of said sensors (12, 13), said signal-processing unit(17) detects the discrete steering angles (α1 to α6) according to adirection and a magnitude of the steering angle, and said sensors (12,13) are protected from an external environmental influence by adetachable sealing cover.
 12. A device according to claim 11, whereinsaid sensors (12, 13) are situated on a side of an axle bridge (2)remote from a forward direction of travel (F).